A new report from the Stockholm International Water Institute is warning that a pending food crisis may force the world's population to adopt a vegetarian diet over the course of the next 40 years. Because livestock require disportionately high rates of water, and given that 9 billion people will need to be fed by 2050, it is thought that the current global trend toward diets rich in animal protein is simply unsustainable.

As it stands, the global population gets about 20% of its protein needs from animal-based products — but according to newly presented research, this will have to drop to just 5% if we're to avoid a food catastrophe. Writing in The Guardian, John Vidal reports:

Dire warnings of water scarcity limiting food production come as Oxfam and the UN prepare for a possible second global food crisis in five years. Prices for staples such as corn and wheat have risen nearly 50% on international markets since June, triggered by severe droughts in the US and Russia, and weak monsoon rains in Asia. More than 18 million people are already facing serious food shortages across the Sahel.

Oxfam has forecast that the price spike will have a devastating impact in developing countries that rely heavily on food imports, including parts of Latin America, North Africa and the Middle East. Food shortages in 2008 led to civil unrest in 28 countries.

Adopting a vegetarian diet is one option to increase the amount of water available to grow more food in an increasingly climate-erratic world, the scientists said. Animal protein-rich food consumes five to 10 times more water than a vegetarian diet. One third of the world's arable land is used to grow crops to feed animals. Other options to feed people include eliminating waste and increasing trade between countries in food surplus and those in deficit.

"Nine hundred million people already go hungry and 2 billion people are malnourished in spite of the fact that per capita food production continues to increase," they said. "With 70% of all available water being in agriculture, growing more food to feed an additional 2 billion people by 2050 will place greater pressure on available water and land."

Vidal also notes that food production will have to increase by 70% by the mid-century mark if we are to have any hopes of meeting demand.

And indeed, it's not enough for the researchers to suggest that switching to a non-meat based diet is the solution. Agriculture in general takes a tremendous toll on the environment and is a major contributor to the ongoing depletion of water reserves. It's estimated, for example, that in the US, withdrawn surface water and groundwater use for crop irrigation exceeds that for livestock by about a ratio of 60:1. The issue, therefore, would seem to be one about the production of potable water and the development of more sustainable agricultural techniques.

The report was released as part of the World Water Conference in Stockholm, Sweden — an annual confab involving over 2,500 politicians, UN bodies, non-governmental groups and researchers from 120 countries who are working to address global water concerns.